#include <REGX52.H>

void Delayms(unsigned int xms)		//@12.000MHz
{
	unsigned char i, j;
	
	while (xms){
		i = 2;
		j = 239;
		do
		{
			while (--j);
		} while (--i);
		xms--;
	}
	
}


void main(){
	while(1){		
		if(P3_1==0){
			Delayms(20);
			while(P3_1==0);
			Delayms(20);
			P2_0=~P2_0;
		}
		
	}
}
